Hybrid new world cichlids--sterile male offspring

[taint damage]

I've a question about hybrids. And, if this has been covered in another thread, forgive me, I didn't find it in my searches.
Ok, so, the way I understand it (and, please correct me if I'm wrong) is, that in hybrids, blood parrots, for example, the males are sterile, but if you were to breed a female back to her father, the resulting male offspring would be fertile.
My question is this: Is it the genetics of the father (species) that allow the fry to be fertile, or might the same hybrid female breeding with another species altogether, i.e. a convict, result in fertile male offspring as well?

 

[aria]

You can get fertile offspring from another species. Most Male bp are sterile but there are fertile ones and if im not mistaken they used hormones to help make them fertile? I believe most of the infertility in the flowerhorn line comes from the f2 generations and beyond. I heard that all kml are fertile. I also heard that white eyes usually have more of a chance of being sterile as opposed to red. But I'm not sure on this fact. I'm sure someone with more knowledge can chime in.